Samatey, F.A. et al. Structure of the bacterial flagellar protofilament and implications for a switch for supercoiling. Nature 410, 331-337

Protonic NanoMachine Project, ERATO, JST, 3-4 Hikaridai, Seika, Kyoto 619-0237, Japan.
Nature (Impact Factor: 41.46). 03/2001; 410(6826):331-337. DOI: 10.1038/35066504


The bacterial flagellar filament is a helical propeller constructed from 11 protofilaments of a single protein, flagellin. The filament switches between left- and right-handed supercoiled forms when bacteria switch their swimming mode between running and tumbling. Supercoiling is produced by two different packing interactions of flagellin called L and R. In switching from L to R, the intersubunit distance (52 Å) along the protofilament decreases by 0.8 Å. Changes in the number of L and R protofilaments govern supercoiling of the filament. Here we report the 2.0 Å resolution crystal structure of a Salmonella flagellin fragment of relative molecular mass 41,300. The crystal contains pairs of antiparallel straight protofilaments with the R-type repeat. By simulated extension of the protofilament model, we have identified possible switch regions responsible for the bi-stable mechanical switch that generates the 0.8 Å difference in repeat distance.

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    • "CD2-1, which contains the active epitope, is composed of the C-terminal D1 and D2 domains. Computer-assisted three-dimensional modeling of N1141 flagellin predicts that the CD2-1 region is located inside in flagellar filament (Supplementary Fig. S1) (Samatey et al. 2001; Yonekura et al. 2003). In addition, the C-terminal region of CD2-1 forms a long, rigid alpha-helical structure, which contributes to flagella filament assembly. "
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    ABSTRACT: Flagellin from the rice avirulent N1141 strain of Acidovorax avenae, functions as a pathogen-associated molecular pattern (PAMP) and induces PAMP-triggered immunity (PTI) in rice. To study the recognition mechanism of flagellin in rice, we attempted to define the region(s) of the flagellin protein required to activate the PTI response. Based on domain classification, we produced four fragments of N1141 flagellin: N-terminal D0, D1 and D2 domains (ND0-2), N-terminal D2, D3, and C-terminal D2 domains (ND2-CD2), C-terminal D2, D1, and D0 domains (CD2-0), and C-terminal D2 and D1 domains (CD2-1). The C-terminal CD2-1 and CD2-0 fragments induced PTI responses in cultured rice cells. Synthetic flg22, which is sufficient to produce the flagellin response in Arabidopsis, and the N-terminal flagellin fragments containing flg22 region elicited very weak immune responses in rice. OsFLS2, the rice ortholog of AtFLS2 which mediates flg22 recognition, was not involved in CD2-0 or CD2-1 recognition in rice. In addition, CD2-0 triggered resistance to coinfection with pathogenic bacteria. Taken together, these data suggest that rice mainly recognizes flagellin CD2-1 by a receptor distinct from OsFLS2, and that this epitope recognition leads to PTI responses.
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    • "Flagellin assembles in a helical pattern of 11 subunits per turn (Yonekura, Maki-Yonekura, & Namba, 2003) with the assistance of the pentameric filament-cap protein FliD (Yonekura, Maki-Yonekura, & Namba, 2001). Crystal structures of Flagellin from S. typhimurium revealed that the protein is composed of three distinct domains: D0, D1, and D2/3 (Samatey et al., 2001) (Figure 1(b)–(d)). The D0 and D1 domains, which comprise the N-and C-termini of Flagellin, respectively, each consist of elongated α-helices and act together with the D1 domain as scaffolds that stabilize the filament structure (Yonekura et al., 2003). "
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    ABSTRACT: The bacterial flagellum is a motility structure and represents one of the most sophisticated nanomachines in the biosphere. Here, we review the current knowledge on the flagellum, its architecture with respect to differences between Gram-negative and Gram-positive bacteria and other species-specific variations (e.g. the flagellar filament protein, Flagellin). We further focus on the mechanism by which the two nucleotide-binding proteins FlhF and FlhG ensure the correct reproduction of flagella place and number (the flagellation pattern). We will finish the review with an overview of current biotechnological applications, and a perspective of how understanding flagella can contribute to developing modules for synthetic approaches.
    No preview · Article · Jul 2014 · Biotechnology & genetic engineering reviews
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    • "Data from related study have shown that the N-terminal D0-D1 domain of flagellin is critically required for TLR5 agonist activity, since a FliC (flagellin from Salmonella typhimurium) molecule containing the N-terminal D0-D1 domain of FlaA (flagellin from H. pylori) was completely inactive [11] [21] [22] . Then the researchers compared the flagellin N-terminal D0-D1 domain amino acid sequences from TLR5-stimulatory bacteria to bacteria that do not activate TLR5, and they found that the highest proportion of amino acid differences between TLR5-stimulatory and nonstimulatory bacteria was within the D1 domain [11] . "
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    ABSTRACT: Objective] Data from ample studies support the idea that the immune homeostasis is crucially dependent on a cross-talk between host immune system and enteric flora in which the host recognizes and responses distinctively to probiotic and pathogenic bacteria. The toll-like receptors (TLRs) and microorganism associated molecular patterns (MAMPs) may play a major role in the host discrimination between probiotics and pathogens, as the recognition of MAMPs by TLRs can activate innate immune response and prime the adaptive immune system. In the TLRs family, TLR5 that responds to flagellin is the only protein-binding TLR, it's much easier to study the flagellin-TLR5 interaction structurally and functionally. The overall aim of this study was to test for a possible contribution of the flagellin-TLR5 crosstalk to the host discrimination between probiotic and pathogenic bacteria. [Methods] Using flagellin protein sequences from probiotic and pathogenic bacteria living in gastrointestinal tract, we firstly constructed a phylogenetic tree of flagellin proteins and then aligned the flagellin protein sequences in TLR5 recognition region between probiotic and pathogenic bacteria. [Results] We found that probiotic and pathogenic bacteria differed in flagellin protein sequence, particularly in the TLR5 recognition sites. [Conclusion] Acclimatization to TLR5 recognition may result in the different TLR5 recognition sites on flagellin between pathogens and probiotics. Moreover, previous studies show that stimulation of basolaterally expressed TLRs results in inflammatory response, but activation of apically expressed TLRs leads to inhibition of the proinflammatory response. Altogether, our findings provide preliminary but encouraging evidence for the existence of crosstalk between flagellin and TLR5 which may be one of the mechanisms for the host discrimination between probiotics and pathogens. Toll 5 1,2,3 1,2 1 4 1* (1. 100101) (2. 100049) (3. 610068) (4. 310036) : Toll (Toll-like receptors TLRs) (Microorganism associated molecular patterns MAMPs) TLRs MAMPs TLRs MAMPs TLR5 TLR5 TLR5 TLR5 TLR5 TLRs TLR5 -5
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